Abstract: The invention provides an injection device for injecting a substance into a subject. The device comprises an injector and an enhancer for enhancing the rate of penetration of the substance into the subject. The injector comprises a microneedle support and at least one microneedle extending from a first surface of said support. The or each microneedle has a fluid channel extending through the microneedle and through the support. The fluid channel of the or each microneedle has an inlet aperture in a second surface of the support and an outlet aperture in the microneedle.